Soluble non-caloric fiber composition and process of preparing the same

ABSTRACT

A process for extracting the water soluble fiber from corn fiber hulls is provided comprising the steps of subjecting the corn fiber hulls to a destarching process, a dewatering process, and exposing the destarched and dewatered corn fiber hulls to a thermochemical treatment to obtain a water-soluble non-caloric corn fiber. A water-soluble non-caloric corn fiber composition is disclosed comprising a destarched corn fiber hull produced by subjecting corn fiber hulls to a non-alkaline destarching process to obtain a destarched corn fiber, dewatering said destarched corn fiber hull, and exposing said destarched and dewatered corn fiber hull to one or more thermochemical treatments to obtain a water-soluble non-caloric corn fiber. Foods and a pharmaceutical comprising the water-soluble non-caloric corn fiber composition are disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a nonprovisional of and claims the benefit ofpriority to U.S. Provisional Patent Application Ser. No. 60/672,794,filed on Apr. 19, 2005, entitled “Soluble Low Calorie Fiber Compositionand Process of Preparing the Same”, having the same named applicants asinventors, namely, Charles Abbas, Kyle E. Beery, and Thomas P. Binder.The entire contents of U.S. Provisional Patent Application Ser. No.60/672,794 is incorporated by reference into this nonprovisional utilitypatent application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application relates to the commercial processing of corn fiberhulls, and, in particular, to the production of a water soluble cornfiber composition. The water soluble corn fiber composition may be usedin food applications as a non-caloric additive or filler or may be usedfor non-food uses.

2. Description of the Background Art

The water soluble fiber extract from the hulls of corn kernels can serveas a non-caloric additive for food and non-food uses. Methods ofextracting the hemicellulosic portion of the corn fiber are well knownin the prior art. In particular, well known prior art methods utilize amulti-step process starting with an alkaline extraction of the cornfiber hemicellulose gum fraction as a whole. The processing of the cornfiber by alkaline extraction utilizes hydrogen peroxide, alkali,protease enzyme, and/or solvents to extract the hemicellulose gum. Thesemethods are expensive because of the multiple steps and materialsneeded. Therefore, it is desirable to develop an economical processutilizing fewer steps and materials.

U.S. Pat. No. 4,038,481 discloses a method of treating corn hulls withalkali to hydrolyze the corn hulls to effect liberation of thehemicellulose fraction.

U.S. Pat. No. 4,957,599 discloses a process for converting nonwoodylignocellulosic substrates into products digestible by ruminants andingestible by humans by forming a slurry of the substrate with anaqueous alkali for wetting of the substrate and subsequently forming aslurry of the wetted substrate in an alkaline peroxide solution toexpose the hemicellulose.

U.S. Pat. No. 5,264,568 discloses a process for preparing a pyrodextrincomprising heating starch in the presence of hydrochloric acid,dissolving the pyrodextrin in water, adjusting the aqueous solution ofthe pyrodextrin to a pH of from 7.0 to 8.5, pre-hydrolyzing the pHadjusted solution with alpha-amylase produced by Bacillus licheniformisto obtain a hydrolysate, adjusting the hydrolysate to a pH of from 5.5to 6.5, hydrolyzing the pH adjusted hydrolysate with alpha-amylase,adjusting the hydrolysate to a pH of 4.0 to 5.0, autoclaving theresulting hydrolysate, hydrolyzing the autoclaved hydrolysate with thealpha-amylase, adjusting the hydrolysate to a pH of 4 to 5, andautoclaving the resulting hydrolysate.

U.S. Pat. No. 5,430,141 discloses a process of preparing low caloriedextrin comprising the steps of heating corn starch in the presence ofmineral acid to prepare pyrodextrin, hydrolyzing the pyrodextrin withalpha-amylase, adding an organic solvent such as ethanol to thehydrolyzed pyrodextrin and recovering low calorie pyrodextrin from thesolvent.

U.S. Pat. No. 6,147,206 discloses a process for the preparation of cornfiber gum comprising mixing corn fiber with an alkaline solution to forma slurry and extract hemicellulose, treating the slurry with hydrogenperoxide at a pH of 10 to 12.5, and separating out the insolublefractions from the corn fiber slurry to yield corn fiber gum insolution.

In spite of this background art, there remains a very real andsubstantial need for an economical process for extracting thewater-soluble portion of corn fiber hulls to yield a water-solublenon-caloric corn fiber that is useful as an additive to animal feed,ingestible for human food consumption, and for non-food uses such as aningredient or filler in a pharmaceutical composition.

SUMMARY

Disclosed herein are cost effective methods for extraction of corn fiberfrom corn hulls as a mixture of water soluble material of varyingmolecular weight polymers comprising oligosaccharides/polysaccharidesand proteins. The water soluble portion of the corn fiber hulls isextracted with a thermochemical treatment after destarching of the cornfiber hulls using a process that employs a non-alkaline and enzymatictreatment of the corn fiber hulls with starch releasing and degradingenzymes. The thermochemical treatment employs a hot water hydrolysisstep to obtain a soluble fiber extract from the treated corn fiberhulls. The hot water solubilized fiber extract prepared with or withoutacid treatment is optionally processed further by any of severalpurification steps, including for example, but not by way of limitation:carbon treatment, ion exchange chromatography, filtration, orcentrifugation to remove impurities such as, for example, coloredcomponents, precipitates formed after extractions or other highmolecular weight material or salts formed in the extracts postextraction and/or concentration. Fractionation of this soluble fiberextract can optionally be further conducted to recover differentmolecular weight preparations that have various food and non-food uses.

A water-soluble non-caloric corn fiber composition is also disclosedcomprising a destarched corn fiber hull produced by subjecting cornfiber hulls to a non-alkaline destarching process (acidic ornon-alkaline enzyme solution) to obtain a destarched corn fiber,dewatering the destarched corn fiber hull, and exposing the destarchedand dewatered corn fiber hull to one or more thermochemical treatmentsto obtain a water-soluble non-caloric corn fiber. In another embodimentof this invention, the composition disclosed herein is a water-solubleoligosaccharide fiber concentrate in solution form. In yet anotherembodiment, the composition is in a dried form.

Another embodiment provides a food comprising a foodstuff and awater-soluble non-caloric corn fiber composition prepared from adestarched corn fiber hull produced by subjecting corn fiber hulls to anon-alkaline destarching process to obtain a destarched corn fiber,dewatering the destarched corn fiber hull, and exposing the destarchedand dewatered corn fiber hull to one or more thermochemical treatmentsto obtain a water-soluble non-caloric corn fiber composition. Thefoodstuff may be any known conventional animal or human consumable foodingredient(s). The food may be an animal feed, or a food suitable forhuman consumption.

In another embodiment, a pharmaceutical composition is providedcomprising a drug and a water-soluble non-caloric corn fiber compositioncomprising a destarched corn fiber hull produced by subjecting cornfiber hulls to a non-alkaline destarching process to obtain a destarchedcorn fiber, dewatering the destarched corn fiber hull, and exposing thedestarched and dewatered corn fiber hull to one or more thermochemicaltreatments to obtain a water-soluble non-caloric corn fiber composition.

DETAILED DESCRIPTION

The process disclosed herein comprises destarching corn fiber hulls andemploying a thermochemical hydrolysis step for solubilizing thedestarched corn fiber to create a composition (preferably a food-gradeproduct) that comprises a hemicellulose-derived fiber that isnon-caloric (i.e., indigestible by humans) and that is useful as a foodadditive, pharmaceutical filler for human or animal consumption. As usedherein, “corn fiber hull” is the pericarp material remaining afterremoving the germ and endosperm from corn grain, typically, but notexclusively, by a wet milling process. The starting corn fiber hullmaterial comprises about 17-25% starch, about 9-13% protein, about40-45% hemicellulose, about 14-18% cellulose, about 2-3% ash, about 3-4%oil, and about 3-6% ferulic acid and coumaric acid. Thearabinoxylan-containing hemicellulose contains 80-90% of the polymermolecular weight as D-xylose and L-arabinose, with the xylan backbonesubstituted with side chains comprising one or more of L-arabinose andD-mannose, D-galactose, ferulic acid, coumaric acid, and D-glucuronicacid accounting for the remaining 10-20% of the polymer molecularweight.

As used herein throughout, the term “about” with reference to a singlevalue means the stated value±10% of the value or ±the degree of accuracyof the measuring instrument, whichever is greater. With reference to arange, “about” means the stated range±20% of the difference between theupper and lower limits of the range or the degree of accuracy of themeasuring instrument, whichever is greater.

In the presently disclosed process, the corn fiber hulls are firstenzymatically destarched to prevent the generation of degradationproducts from the breakdown of glucose, which is derived mainly from thehydrolysis of starch, during the thermochemical step. The destarchingstep comprises placing the as-is corn fiber hulls obtained from a wetmilling plant (typically having a moisture content ranging from about45% to about a 70% by weight water, and more typically from about a 53%to about a 65% by weight water) in a sufficient amount of water toobtain a mixture that has about a 10-15% by weight corn fiber hullsolids content. If the corn fiber hulls are obtained from a dry millingplant the moisture content can be adjusted to obtain the same levels forthe mixture. The mixture is treated to a temperature ranging from about35° C. to about 70° C., and more typically at about 50° C., in astandard jacketed half-moon tank at ambient pressure, and the mixture isadjusted to a non-alkaline pH ranging from about 3 to about 5 with aninorganic acid (mineral acid). In certain embodiments, it isparticularly advantageous to use sulfuric acid as the inorganic acid. Tothe mixture is added from about 0.01 to about 1.0%, and typically about0.05% (total weight enzyme/weight dry corn fiber) of a starch degradingenzyme. In certain embodiments, the starch degrading enzyme is a mixturethat comprises equal parts of α-amylase and another starch degradingenzyme such as glucoamylase. The mixture with enzyme is held at atemperature and for a time sufficient to hydrolyze at least a majorityof the starch in the corn fiber hulls. In exemplary practice, thetemperatures is about 50° C. to about 90° C., and typically about 60°C., and the time is from about 0.1 hour to about 24 hours, and typicallyabout 16 hours. The mixture is churned, for example by agitating with ablade agitator at an RPM ranging from about 100 to about 800 RPM,typically about 150 RPM. The agitation speed is not important so long asthe mixture can be fully intermixed. A tumbler is a suitable alternativeto an agitator for large scale embodiments.

The hydrolysis of the starch yields a mixture containing a solublecomponent comprising primarily glucose and an insoluble componentcontaining a crude fiber mixture comprised primarily of cellulose andhemicelluloses. The crude insoluble fiber from the destarching step isdewatered (i.e., liquid is removed therefrom) using a suitablesolid/liquid separation technique. Suitable non limiting examplesinclude filtration, precipitation, centrifugation and use of screwpress. One exemplary embodiment utilizes a Vincent press set at fromabout 10 to about 60 Hz, and more preferably at about 20 Hz (VincentCorporation, Tampa, Fla.), washed utilizing an equivalent weight ofwater as the corn fiber employing from about 1-3 equivalent weights. Thecrude fiber fraction is dewatered again utilizing the Vincent press tofurther remove the solubilized liquid fraction. When not using a screwpress, the crude fiber fraction may be washed by spraying andcentrifugation, spraying and filtration, by resuspension and filtrationor any other means available to one of skill in the art to wash a fiberfraction with a solvent (e.g., water) in which the fiber is insoluble.

The washed crude fiber fraction is then subjected to a thermochemicalhydrolysis step where the crude fiber is treated to elevatedtemperatures in the presence of water and optionally with added acid.Even if no additional acid is added, the treatment is stillthermochemical because a (i) a portion of the acid from the destarchingstep is carried over with the crude fiber, (ii) a portion of free acids,such as lactic acid present in the original corn fiber hull materialremains with the crude fiber, and (iii) the breakdown products fromtreating the crude fiber fraction to heat in the presence of waterincludes acetic acid released from the hemicellulose present in thecrude fiber fraction. In an exemplary embodiment, the thermochemicalheating is conducted utilizing a pressure reactor having a rotatingpressure tank at a temperature from about 130° C. to about 175° C.,typically at about 145° C. and at a pressure of from about 2.70 bar toabout 8.92 bar, and typically at about 5.1 bar for about 1 to 60minutes, typically about 30 minutes. In an exemplary practice the tankis rotated, at from about 0.1 to 10 RPM and in one practice, at about 1RPM.

This thermochemical treatment step hydrolyzes a portion of thehemicellulose into a soluble fraction comprising monosaccharides(primarily xylose) and small soluble oligosaccharides that areindigestible by humans (i.e., water soluble non-caloric fiber). Theother fraction remains an insoluble crude fiber fraction containingcellulose, along with the unhydrolyzed portion of the hemicellulose.Optionally, the insoluble crude fiber fraction may be further dewateredand subjected to a second thermochemical treatment to obtain moresoluble fiber. In one exemplary practice, the fiber from the firstthermochemically treated mixture is first dewatered utilizing a Vincentpress set at from about 10 to about 60 Hz, atypically at about 20 Hz(Vincent Corporation, Tampa, Fla.) to obtain the liquid fractioncontaining the soluble fiber, and the insoluble fiber residue is washedutilizing from about 1 to 3 equivalent weight of water and dewateredagain utilizing the Vincent press to further extract any solubilizedfiber prior to being treated to a second thermochemical heating step.

In certain embodiments, a single thermochemical treatment stephydrolyzes at least about 30% (typically about 30-50%) of thehemicellulose into water soluble fiber. In other embodiments to increaseyield, the soluble fraction may be removed from the crude fiber and thecrude fiber may be subjected to a second thermochemical treatment tofurther obtain a second soluble fraction containing the water solublenon-caloric fiber. In any case, the overall hydrolysis is similar to thethermochemical hydrolysis of the non-destarched corn fiber hulls;however, the amount of Maillard reaction byproducts is much low, leadingto a lighter colored product.

The water soluble fraction containing the monosaccharides and watersoluble fiber prepared by the methods herein may be characterized inseveral ways. In one characterization, the solid content of the watersoluble fraction comprises at least about 10% of oligosaccharides havinga degree of polymerization greater than 2. In another characterization,the water soluble fraction comprises at least about 20% ofoligosaccharides having a degree of polymerization greater than 2. Inyet another characterization, the water soluble fraction comprises atleas about 30% of oligosaccharides having a degree of polymerizationgreater than 2. In still another characterization, the ratio of watersoluble oligosaccharides having a degree of polymerization between 2 and9 to monosaccharides is at least about 10%, at least about 20%, at leastabout 30% and in some embodiments, at least about 40%. In yet anothercharacterization, the ratio of water soluble oligosaccharides having adegree of polymerization between 8 and 9 to water solubleoligosaccharides having a degree of polymerization between 2 and 7 is atleast 0.8 and in certain embodiments, between about 0.8 and about 3.0.In still yet another characterization, the composition may becharacterized by any of the foregoing ratios of carbohydrate materialand further contains a protein component derived from hemicellulose. Theliquid fraction containing the soluble fiber is separated from theinsoluble crude fiber fraction by any suitable solid/liquid separationstep and the liquid fraction is retained. The liquid fraction may beconcentrated to provide a concentrated soluble fiber product or dried toprovide a solid soluble fiber product.

The liquid fraction can be optionally processed by any of a number ofmethods known by those skilled in the art to remove impurities or othercomponents, for example when the soluble fiber is to be used as foodadditive or particularly when the fiber is used a pharmaceutical orpharmaceutical additive. In certain embodiments the liquid fraction maybe treated to sizing techniques such as chromatography or precipitationto select fractions containing various distributions of size ranges ofthe soluble fiber, or specifically to remove monosaccharides anddisaccharides from the liquid fraction. Suitable methods that may beemployed, include but are not limited to: ion exchange chromatography(for example, strong acid or strong base cation exchange chromatographytypically conducted at a ambient temperatures, with a flow rates of fromabout 1-20 bed volumes per hour; a carbon column treatment at underambient conditions with similar flow rates; membrane ultrafiltrationutilizing a 100K molecular weight cut off membrane filtration unit atpressures ranging from about 25 to 150 psi pounds per square inch;filtration using a filter aid with diatomaceous earth and a suitablevacuum—(e.g., 30 in Hg (−762 torr; and centrifugation, for example,utilizing a disk-stack type centrifuge.

An optional treatment on the soluble fiber-containing liquid could be afermentation step for the purpose of removing any fermentable sugarsfrom the mixture. This would ensure the removal of any glucose, xyloseor other monosaccharides or maltose and other digestible disaccharides,which are both digestible by humans from the final product. This couldtake place at a temperature range from about 28° C. to about 35° C., andpreferably at 30° C. with Saccharomyces cerevisiae in a fermentor at apH ranging from about 3.5 to about 5.5 and preferably at pH 4.5 withagitation at 100 RPM at ambient pressure. As mentioned, the liquidcontaining the soluble fiber can be further processed to create a watersoluble fiber-concentrate or a dry fiber product. One example method ofdrying the fiber composition is to spray-dry the liquid utilizing an APVCrepaco, Inc spray dryer with an inlet temperature ranging from about200° C. to about 300° C. and preferably at about 260° C. and an outlettemperature ranging from about 50° C. to about 150° C. and preferably atabout 86° C. The dry product or concentrate can be used as a non-caloricfiller in human food applications, or for various uses in non-foodapplications such as a pharmaceutical additive.

EXAMPLES

The following examples demonstrate the instant invention in greaterdetail. These examples are not intended in any way to limit the scope ofthis invention in any way.

Example I

50 mL each of four starch degrading enzymes obtained from commercialsources Genencor International and Novozymes; two α-amylase enzymes (EC3.2.1.1. Spezyme FRED and Termamyl SC) and two amyloglucosidase enzymes(EC 2.2.1.3, Spirizyme Plus and Optidex L-400) were added to 20.7 kg(41.26% solids; 8.55 kg dry weight basis (d.w.b.)) of corn fiber. Atotal of 44.2 kg of deionized water were added to the corn fiber slurryto lower the solids content to 13% dry solids. The slurry was held atabout 60° C. in the tumbler reactor, which was rotating at about 1 RPM,for about 20 hrs. After the starch hydrolysis, the corn fiber wasmechanically dewatered to 42.3% solids by processing with a screw press.After the starch hydrolysis, 15.6 kg (6.62 kg d.w.b.) of fiber remained,therefore 22.6% of the fiber had been solubilized by the starchhydrolysis step. The remaining fiber was split into two 7.82 kg (3.31 kgd.w.b.) batches of destarched corn fiber for subsequent thermochemicalhydrolysis. The first 7.82 kg batch of destarched corn fiber washydrolyzed as is without addition of acid, and the second batch washydrolyzed with the addition of acid.

Example II

The first batch of destarched fiber was mixed with 11.3 kg of deionizedwater to lower the solids concentration to 17.3%. The fiber washydrolyzed in the tumbler reactor at about 141° C. and about 1 RPM forabout 30 minutes at a pressure of about 5.1 bar. The amount of time ittook to reach the hydrolysis temperature was approximately 20 minutesand the depressurization step was completed in approximately 15 minutesto reach ambient pressure. 0.22 kg of steam condensate was added to thecorn fiber during the thermochemical hydrolysis step. After thethermochemical hydrolysis, the fiber was mechanically dewatered in ascrew press, resulting in 10.7 kg of extract with a pH of 3.45. Thefiber was washed with water and mechanically dewatered again to 42.3%solids, resulting in 13.9 kg of wash extract with a pH of 3.40. The massof the remaining fiber was 4.99 kg (2.11 kg d.w.b.), therefore 36.2% ofthe fiber had been solubilized by the thermochemical treatment, and50.7% overall (destarching and thermochemical hydrolysis).

Example III

The second batch of fiber (7.82 kg) was treated with 0.3% sulfuric acid(23.5 g). The sulfuric acid was mixed into a total of 12.7 kg of water,and the liquid was added to the fiber to decrease the solids content to16.1%. The fiber was hydrolyzed in the tumbler reactor at about 141° C.and about 1 RPM for about 30 minutes and at a pressure of 5.1 bar. Theamount of time it took to reach the hydrolysis temperature wasapproximately 20 minutes and the depressurization step was completed inapproximately 15 minutes to reach ambient pressure. 0.73 kg of steamcondensate was added to the corn fiber during the thermochemicalhydrolysis step. After the thermochemical hydrolysis step, the fiber wasmechanically dewatered in a screw press, resulting in 13.5 kg of extractwith a pH of 2.50. The fiber was washed with water and mechanicallydewatered again to 39.93% solids, resulting in 12.8 kg of extract with apH of 2.80. The mass of the remaining fiber was 4.42 kg (1.77 kgd.w.b.), therefore 46.6% of the fiber had been solubilized by thethermochemical treatment, and 58.7% overall (destarching andthermochemical hydrolysis).

The corn fiber hydrolysate extracts of Examples I and II prepared fromthe soluble corn fiber preparation obtained without acid addition orafter acid addition, respectively, were filtered through a VWR 417(fast, qualitative) 11.0-cm paper filter in a Buchner funnel attached toa vacuum filter flask. A pre-coat of filter aid diatomaceous earth waspoured over the filter prior to introducing the hydrolysates.

The procedure for pouring the filter aid pre-coat was as follows:

-   -   a. Place the filter in the Buchner funnel assembly;    -   b. Mix the filter aid slurry in a breaker with deionized        water (DI) water;    -   c. Wet the filter with DI water while attached to the vacuum        line; and    -   d. Pour the filter aid slurry slowly at first, and then rapidly        to form the pre-coat.

After the pre-coat was poured, the hydrolysate was filtered until thetop layer of the pre-coat was blocked with solids. At this point, thetop layer of the pre-coat was scraped off and the hydrolysate wasfiltered until the filter aid became blocked with solids again. The toplayer was then scraped and the cycle was repeated until the pre-coat wasremoved. At this point, a new filter and filter aid pre-coat wereapplied and the process was repeated.

Protein and DP Analysis for the Soluble Corn Fiber OligosaccharideHydrolysates

Four samples for protein and DP (degree of polymerization) analysis wereprepared for the corn fiber oligosaccharide hydrolysates as follows: (1)hydrolyzed (no acid) and unfiltered; (2) hydrolyzed (no acid) andfiltered; (3) acid hydrolyzed and unfiltered; and (4) acid hydrolyzedand filtered.

Protein Analysis from Corn Fiber Hydrolysates

The protein concentration of the four hydrolysates (1-4 above) wasanalyzed by the Bradford assay (Bradford, M. M. “A rapid and sensitivemethod for the quantitation of microgram quantities of protein utilizingthe principle of protein-dye binding”, Anal Biochem. 1976 May 7;72:248-54) as known by those skilled in the art.

Bradford Protein Assay

An estimate of the protein concentration for the samples was used forthe four samples listed above. The acid-treated hydrolysates had a drysolids level of about 6.56% and the non-acid-treated hydrolysates had adry solids level of about 5.3%. The protein levels were estimated to beabout 5.9 g/L in the acid treated hydrolysates and about 2.6 g/L in thenon-acid-treated hydrolysates. Therefore, the proper dilution factor is1000× for each sample, so each sample was diluted 1000× to obtainprotein concentrations between 2 and 10 ppm (parts per million). Theinstructions for the Bradford Assay as listed above were carried out andthe absorbance of the standards and samples were determined. Theconcentrations and absorbencies as analyzed in the standards were usedto plot the standard curve and to obtain the slope and intercept, whichwere used to calculate the protein concentrations in the experimentalsamples. Table 1 shows the calculated protein concentrations of the fourexperimental samples.

DP Analysis

The four experimental samples were analyzed for monosaccharides andoligosaccharides with up to a degree of polymerization (DP) of 9 bychromatography. The results are shown in Table 2.

Results

The protein analysis (Table 1) shows that the protein concentration isincreased by the presence of acid in the hydrolysis procedure, butremoved by the filtration step using filter aid as set forth herein.

Using acid in the hydrolysis step decreases the degree of polymerization(DP2 to DP9) of the oligosaccharides in the hydrolysates, this is mostlikely because the liberated oligosaccharides are immediately degradedto monosaccharides or degradation products. This reaction is catalyzedby the sulfuric acid present in the liquid.

The filtration step removed nearly all of the degree of polymerization(DP2 to DP9) of oligosaccharides and a large fraction of themonosaccharides, as well as the protein (as set forth herein).

The filtration media absorbs a large portion of the protein,oligosaccharides, and monosaccharides in the hydrolysates. The resultsshow that preferably, the hydrolysates are to be used as-is withoutfiltration. For the unfiltered hydrolysates, a large peak appears at thebeginning of the chromatogram when the hydrolysate is analyzed, and thispeak is likely composed of larger oligosaccharides, or highly branchedoligosaccharides. More preferably, the results show that the unfilterednon-acid prepared hydrolysate is the fraction that is most important ifthe hydroysateis to be used as a food-grade fiber, non-caloric additive,or filler. Table 1: Calculated Protein Concentrations by BradfordAnalysis.

TABLE 1 Protein analysis of soluble fiber from corn fiber hulls PPMProtein (parts per Concentration in Samples million) Absorbance Sample(g/L) 1. No Acid, unfiltered 2.85 0.509 2.85 2. No Acid, filtered 0.910.478 0.91 3. Acid, unfiltered 4.85 0.541 4.85 4. Acid, filtered 1.540.488 1.54

TABLE 2 DP Analysis by Chromatography (values in grams/liter) Sample IdDP8-DP9 DP2-DP7 DP1 1. No acid, un-filtered 2.70 0.90 8.90 2. No acid,filtered 0 0.10 2.60 3. Acid, un-filtered 0.40 0.50 9.60 4. Acid,filtered 0 0 6.20

Samples containing water soluble corn fiber were spray dried using anAPV Crepaco, Inc. spray dryer. The inlet temperature was kept atapproximately 260° C. and the outlet temperature was approximately 86°C. The extracts were pumped through the spray dryer nozzle and thematerial dried and agglomerated and pneumatically conveyed out of thedryer. In one example, from above the acid-treated water soluble cornfiber extract produced 350.8 g of material and the non-acid treatedwater soluble corn fiber extract produced 256.45 g of material.

The methods and processes illustratively described herein may besuitably practiced in differing orders of steps. They are notnecessarily restricted to the orders of steps indicated herein or in theclaims.

As used herein and in the appended claims, the singular forms “a,” “an,”and “the” include plural reference unless the context clearly dictatesotherwise.

Under no circumstances may the patent be interpreted to be limited tothe specific examples or aspects or methods specifically disclosedherein. Under no circumstances may the patent be interpreted to belimited by any statement made by any Examiner or any other official oremployee of the Patent and Trademark Office unless such statement wasspecifically and without qualification or reservation expressly adoptedby Applicants in a responsive writing specifically relating to theapplication that led to this patent prior to its issuance.

The terms and expressions employed herein have been used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions, or any portions thereof, to exclude anyequivalents now known or later developed, whether or not suchequivalents are set forth or shown or described herein or whether or notsuch equivalents are viewed as predictable, but it is recognized thatvarious modifications are within the scope of the invention claimed,whether or not those claims issued with or without alteration oramendment for any reason. Thus, it shall be understood that, althoughthe present invention has been specifically disclosed by preferredembodiments and optional features, modifications and variations of theinventions embodied therein or herein disclosed can be resorted to bythose skilled in the art, and such modifications and variations areconsidered to be within the scope of the inventions disclosed andclaimed herein.

Specific methods and compositions described herein are representative ofpreferred embodiments and are exemplary and not intended as limitationson the scope of the invention. Other objects, aspects, and embodimentswill occur to those skilled in the art upon consideration of thisspecification, and are encompassed within the spirit of the invention asdefined by the scope of the claims. Where examples are given, thedescription shall not be construed to include but not to be limited toonly those examples. It will be readily apparent to one skilled in theart that varying substitutions and modifications may be made to theinvention disclosed herein without departing from the scope and spiritof the invention, and from the description of the inventions, includingthose illustratively set forth herein, it is manifest that variousmodifications and equivalents can be used to implement the concepts ofthe present invention without departing from its scope. A person ofordinary skill in the art will recognize that changes can be made inform and detail without departing from the spirit and the scope of theinvention. The described embodiments are to be considered in allrespects as illustrative and not restrictive. Thus, for example,additional embodiments are within the scope of the invention and withinthe following claims.

Whereas particular embodiments of this invention have been described forpurposes of illustration, it will be evident to those persons skilled inthe art that numerous variations of the details of the present inventionmay be made without departing from the invention as defined in theappended claims.

1. A process for extracting the water-soluble portion of corn fiberhulls to obtain a water-soluble non-caloric corn fiber comprising thesteps of: subjecting said corn fiber hulls to a destarching process toobtain a destarched corn fiber, wherein said destarching processcomprises treating a water and corn fiber mixture in the absence of analkaline compound, at a temperature between about 35° C. and about 70°C. and at a pH from about 3 to about 5 in the presence of astarch-degrading enzyme mixture consisting of alpha-amylase andglucoamylase; dewatering said destarched corn fiber; and exposing saiddewatered and destarched corn fiber to a thermochemical treatment toobtain a liquid fraction containing water-soluble non-caloric cornfiber, wherein said thermochemical treatment comprises elevating thetemperature of the corn fiber to between about 130° C. to about 175° C.at a pressure of between about 2.70 bar to about 8.92 bar, in thepresence of water and, optionally, acid.
 2. The process of claim 1wherein said destarching process comprises forming a mixture of waterand corn fiber hulls; adjusting the pH of said water-corn fiber hullmixture to a non-alkaline pH; and contacting the mixture with a starchdegrading enzyme in an amount and for a time sufficient to hydrolyze amajority of starch in corn fiber hull.
 3. The process of claim 2 whereinsaid thermochemical treatment comprises a hot water hydrolysis of saidtreated corn fiber at a temperature ranging from about 130° C. to about175° C. for a time sufficient to hydrolyze at least about 30%—of thehemicellulose present in the destarched corn fiber.
 4. The process ofclaim 3 comprising the steps of performing a first dewatering of saiddestarched corn fiber hulls utilizing a screw-type press; washing saiddestarched corn fiber hulls with water and performing a seconddewatering of said destarched corn fiber hulls utilizing a screw-typepress.
 5. The process of claim 1 wherein the thermochemical treatmentincludes addition of an inorganic acid.
 6. The process of claim 5wherein said inorganic acid is sulfuric acid.
 7. The process of claim 1wherein the thermochemical treatment does not include addition of aninorganic acid.
 8. The process of claim 1 further comprising treatingsaid liquid fraction to remove impurities that are not water solublecorn fiber.
 9. The process of claim 8 wherein said step of treating saidliquid fraction includes performing at least one process selected fromthe group consisting of ion exchange chromatography, carbon columntreatment, membrane filtration, filtration using a filter aid andcentrifugation.
 10. A process for extracting the water-soluble portionof corn fiber hulls to obtain a water-soluble non-caloric corn fibercomprising the steps of: subjecting said corn fiber hulls to adestarching process to obtain a destarched corn fiber, wherein saiddestarching process comprises treating a water and corn fiber mixture inthe absence of an alkaline compound, at a temperature between about 35°C. and about 70° C. and at a pH from about 3 to about 5 in the presenceof a starch-degrading enzyme mixture consisting of alpha-amylase andglucoamylase: dewatering said destarched corn fiber; and exposing saiddewatered and destarched corn fiber to a thermochemical treatment toobtain a liquid fraction containing water-soluble non-caloric cornfiber, wherein said thermochemical treatment comprises elevating thetemperature of the corn fiber to between about 130° C. to about 175° C.at a pressure of between about 2.70 bar to about 8.92 bar, in thepresence of water and, optionally, acid, wherein said liquid fraction isfermented with a micro organism that does not digest the water solublecorn fiber to remove fermentable sugars from said liquid fraction. 11.The process of claim 1 further comprising drying at least one of saidliquid or a water soluble corn fiber obtained from said liquid fractionby processing with a spray dryer, drum dryer, or other drying equipmentto create a dry water soluble corn fiber containing product.
 12. Theprocess of claim 1 wherein the destarching comprises contacting the cornfiber hulls with ea starch degrading enzyme in the form of a mixture oftwo or more starch degrading enzymes.
 13. The process of claim 12wherein said one or more starch degrading enzymes includes at least oneof an α-amylase enzyme and at least one of an amyloglucosidase enzyme.14. The process of claim 12 wherein said mixture of said starchdegrading enzymes comprises equal parts of each of said starch degradingenzymes.
 15. The process of claim 1 wherein the liquid fraction ischaracterized by having at least 20% of dissolved solids comprising awater soluble corn fiber having a DP of greater than 2, and with ameasurable portion having a DP of 8-9.